﻿using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization.Json;
using System.Text;
using System.Text.RegularExpressions;
using System.Web;

namespace WebUI.Helper
{
    public class JsonHelper
    {
        /// <summary>
        /// JSON序列化
        /// </summary>
        /// <typeparam name="T">序列化对象类型</typeparam>
        /// <param name="t">序列化对象</param>
        /// <returns>字符串</returns>
        public static string JsonSerializer<T>(T t) 
        {
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
            //MemoryStream ms = new MemoryStream();
            //ser.WriteObject(ms, t);
            string jsonString = "";
            
            //日期转化
            string p = @"\\/Date\((\d+)\+\d+\)\\/";
            MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString);

            using (MemoryStream stream = new MemoryStream())
            {
                ser.WriteObject(stream, t);
                jsonString = Encoding.UTF8.GetString(stream.ToArray());
            }
            Regex reg = new Regex(p);
            jsonString = reg.Replace(jsonString, matchEvaluator);
            return jsonString;
        }

        /// <summary>
        ///  JSON反序列化
        /// </summary>
        /// <typeparam name="T">泛型对象</typeparam>
        /// <param name="jsonString">字符串</param>
        /// <returns>对象</returns>
        public static T JsonDeserialize<T>(string jsonString)
        {
            //将"yyyy-MM-dd HH:mm:ss"格式的字符串转为"\/Date(1294499956278+0800)\/"格式
            string p = @"\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}";
            MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertDateStringToJsonDate);
            Regex reg = new Regex(p);
            jsonString = reg.Replace(jsonString, matchEvaluator);

            using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString)))
            {
                DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
                T obj = (T)ser.ReadObject(ms);
                return obj;
            }
           // MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
        }

        /// <summary>
        /// 将Json序列化的时间由/Date(1294499956278+0800)转为字符串
        /// </summary>
        /// <param name="m"></param>
        /// <returns></returns>
        private static string ConvertJsonDateToDateString(Match m)
        {
            string result = string.Empty;
            DateTime dt = new DateTime(1970, 1, 1);
            dt = dt.AddMilliseconds(long.Parse(m.Groups[1].Value));
            dt = dt.ToLocalTime();
            result = dt.ToString("yyyy-MM-dd HH:mm:ss");
            return result;
        }

        /// <summary>
        /// 将时间字符串转为Json时间
        /// </summary>
        /// <param name="m"></param>
        /// <returns></returns>
        private static string ConvertDateStringToJsonDate(Match m)
        {
            string result = string.Empty;
            DateTime dt = DateTime.Parse(m.Groups[0].Value);
            dt = dt.ToUniversalTime();
            TimeSpan ts = dt - DateTime.Parse("1970-01-01");
            result = string.Format("\\/Date({0}+0800)\\/", ts.TotalMilliseconds);
            return result;
        }
    }
}